Seam for papermachine clothing

ABSTRACT

A protective cover for a press fabric seam of a press fabric on the roll side of the fabric. The protective cover has a first portion and a second portion. The first portion is attached to a press fabric first seam portion such that the first portion is attached to the roll side of the press fabric.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 of U.S.Patent Application No. 60/711,587 filed Aug. 26, 2005, the disclosure ofwhich is expressly incorporated by reference herein in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A COMPACT DISK APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a fabric used in papermaking. Morespecifically, the present invention relates to a press felt having animproved seam and method for seaming that protects the loops from wearand abrasion on the roll side of the fabric.

2. Description of Background

EP1127976 A2 and U.S. Pat. No. 6,712,940, are incorporated herein byreference. These patents disclose a papermachine belt having athermoplastic composite surface, the belt is on-machine seamed, and thebelt is seam sealed using thermoplastic means and materials.

Various methods are known for seaming paper machine fabrics along withthe use of resin materials. For example, in U.S. Pat. No. 2,151,329, aprocess belt has a resin coated surface. The belt is cut over the seam,and a mixture of resin and blowing agent is applied to the cut after thebelt is pinned on the paper machine. Heat is then applied to activatethe blowing agent to foam and fill the voids and cure the resin.

In U.S. Pat. No. 5,601,877, the belt is processed similarly to U.S. Pat.No. 2,151,329 discussed above, except the seam is impregnated withaviscous paste.

In U.S. Pat. No. 4,948,646 for a seam felt, the surface of the seam flapis provided with a resilient support material to impart a compressionrecovered thickness equal to or greater than the rest of the felt. Thisis then held in place utilizing a low melt adhesive.

In U.S. Pat. No. 5,789,052 for a processing belt, the coating that isused is of a polymeric resin material. The seam is covered on theuncoated side of the belt with an encapsulating material. Theencapsulating material is a paste of resin and foaming agent.

It is also known to add silicone “silastic” to the roll side of seamfelts after pinning on the paper machine.

It is also known to add a polyamide resin to the seam from the sheetsideafter pinning on the paper machine.

In older methods, no flap is formed, rather a gap is created that mustbe filled with resin, foaming agent, etc. on the paper machine. It iswell known that this method in practice leads to sheet marking from theseam, from, for example, uneven application of the resin paste, unevenhigh temperature curing on the paper machine, and/or the resin pastelosing adhesion in use, and/or wearing off to create a nonuniform gap.Furthermore, the cured resin paste will not have the same smoothness andsurface properties compared to the rest of the felt, both when the feltis new and when it wears, which also leads to sheet marking and sheettransfer difficulties.

There is, however, an inherent problem in that for all of the aboveseams, none protect the seam loop from wear and abrasion on the rollside of the fabric. Accordingly, there is a need for an apparatus andmethod of applying a protective measure on the roll side of the fabric.

BRIEF SUMMARY OF THE INVENTION

In current PMC press felt seams, the seam loops are not protected fromwear and abrasion on the roll side of the fabric. This is a result ofthe needled batt being removed in order to seam the felt on the papermachine.

One objective of this invention is a protective cover that extends overthe exposed seam loop while on the paper machine, protecting the seam,and more importantly, the loops, from being exposed to wear and abrasionwhile running on the paper machine.

To protect the seam and the loops on the papermachine roll side, a flapor protective cover is used. The flap, or protective cover, isfabricated from a solid film or a scrim type plastic material. Theprotective cover can be permeable or impermeable. One side of theprotective cover is attached to the leading edge of the fabric on theroll side. Attachment of the protective cover to the fabric can be viaan adhesive or casting.

In this manner, after a seam loop area has been created, a protectivecover can be applied. When the protective cover is a strip, a firstportion of the strip, for example one side edge of the strip can beneedled to the batt fiber to hold the side edge of the strip to thefabric. This creates a hinge in a middle portion of the strip, and afree moving third portion, or flap of the strip. The hinge is preferablyon the leading side portion of the fabric. In this manner, the thirdportion or flap of the strip will naturally fall into the properposition thereby protecting the loops in the seam area. The thirdportion or flap of the strip extends over all or part of the entire seamloop area. Preferably the flap extends at least to the portion of theseam area where the pintle is located.

In another embodiment, the first portion of the strip is attached to orincorporated into the base of the fabric, arranged so that the thirdportion, or flap, is exposed after the fabric is needled.

The protective cover or strip can also be formed from needled battfibers, optionally reinforced with an adhesive resin.

In another embodiment, the first portion of the protective cover orstrip can be embedded within the layers of the needled batt.

These and other features and advantages of this invention are describedin or are apparent from the following detailed description of thepreferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the present inventions is further describedin the detailed description which follows, in reference to the notedplurality of drawings by way of non-limiting examples of exemplaryembodiments of the present invention, in which like reference numeralsrepresent similar parts throughout the several views of the drawings,and wherein:

FIG. 1 is a cross-section of a prior art paper machine fabric on-machineseam;

FIG. 2 is a cross section of a paper machine fabric with a flap attachedto the roll side batt of a fabric of the present invention after theseam is complete.

DETAILED DESCRIPTION OF THE INVENTION

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the embodiments of the present invention onlyand are presented in the cause of providing what is believed to be themost useful and readily understood description of the principles andconceptual aspects of the present invention. In this regard, no attemptis made to show structural details of the present invention in moredetail than is necessary for the fundamental understanding of thepresent invention, the description taken with the drawings makingapparent to those skilled in the art how the several forms of thepresent invention may be embodied in practice.

FIG. 1 shows a cross-section of a prior art paper machine fabric 10on-machine seam. The fabric 10 has a paper side 12 and a paper machineroll side 14. Loops 16 are interconnected such that a pintle 18 can beinserted.

Batt 20 is cut near the loops 16 on the paper side 12. On the papermachine roll side 14, the roll side batt 22 may be cut or removed fromthe area 24 about the loops 16, allowing the fabric 10 to be flexible insuch a manner that the seam can be completed on the paper machine. Thisresults in a void area 26 on the roll side 14 about the loops 16.

FIG. 2 is a cross section of a paper machine fabric 100 having a paperside 112 and a paper machine roll side 114. Loops 116 are interconnectedsuch that a pintle 118 can be inserted.

Batt 120 is cut near the loops 116 on the paper side 112. On the papermachine roll side 114, the roll side batt 122 may be cut or removed fromthe area 124 about the loops 116, allowing the fabric 100 to be flexiblein such a manner that the seam can be completed on the paper machine.This results in a void area 126 on the roll side 114 about the loops116. A flap 128 is attached to the roll side batt 122 of a fabric of thepresent invention prior to seaming.

The flap 128 has an attached portion 130 and an unattached portion 132.The attached portion 130 is attached to the roll side batt 122 offcentered or to the side of the loops 116 at a first seam portion 140.

In the preferred embodiment, the flap 128 is approximately 0.38 mm thickpolyurethane member, approximately 10 mm wide and extending across theentire width of the press fabric 100. The flap 128 is positioned with afirst edge, or the attached portion 130, is approximately 4 mm in frontof the seam loops on the leading edge of the roll side 114 of the fabric100. This first edge 130 is “thermo-bonded” and thereby securely bondedinto the felt structure with minimal calliper addition. The second edgeof the member, or the unattached portion 132, extends over and past theloops, thereby protecting the loop yams from wear and abrasion.

It should be noted that the unattached portion 132 is not required toextend pat the loops, rather, depending on the application, can beadjusted to cover a predetermined portion of the seam loop area 124,randing from partially covering the loops to extending fully across theseam loop area 124 and beyond.

The flap or protective cover 128 is fabricated from a solid film or ascrim type plastic material. The flap 128 can be permeable orimpermeable. One side of the flap is attached to the leading edge of thefabric on the rollside. Attachment of the flap to the fabric can be viaan adhesive or casting.

In this manner, after a seam loop area 124 has been created, aprotective cover or flap 128 can be applied.

In a second embodiment, the protective cover or flap 128 is a strip, andone side edge of the strip 130 is needled to the batt fiber to hold theside edge of the strip to the fabric 100. This creates a hinge 134. Thehinge 134 is preferably on the leading side edge of the fabric. In thismanner, the protective strip will naturally fall into the properposition thereby protecting the seam area.

While the present invention has been particularly shown and describedwith reference to the foregoing preferred embodiments, those skilled inthe art will understand that many variations may be made therein withoutdeparting from the spirit and scope of the invention as defined in thefollowing claims. This description of the invention should be understoodto include all novel and non-obvious combinations of elements describedherein, and claims may be presented in this or a later application toany novel and non-obvious combination of these elements. The foregoingembodiments are illustrative, and no single feature or element isessential to all possible combinations that may be claimed in this or alater application. Where the claims recite “a” or “a first” element orthe equivalent thereof, such claims should be understood to includeincorporation of one or more such elements, neither requiring norexcluding two or more such elements.

1. A protective cover for a press fabric seam, comprising: a pressfabric having a paper side and a roll side; a protective cover, theprotective cover having a first portion and a second portion; whereinthe first portion is attached to a press fabric first seam portion; andwherein the first seam portion is attached to the roll side of the pressfabric.
 2. The protective cover of claim 1, the press fabric having seamloops, wherein the first portion is attached to the first seam portionoff center of the seam loops.
 3. The protective cover of claim 2,wherein the first portion is attached approximately 4 mm in front of theseam loops.
 4. The protective cover of claim 2, wherein the secondportion extends over a first portion of a seam loop area.
 5. Theprotective cover of claim 1, wherein the protective cover is at leastone of a scrim, a solid film, a plastic material, a woven material, anda non-woven material.
 6. The plastic cover of claim 1, wherein theprotective cover is permeable or impermeable.
 7. The protective cover ofclaim 1, wherein the first portion is attached to the first seamportion.
 8. The protective cover of claim 7, wherein the first portionis attached to the first seam portion by at least one of needling andadhesive.
 9. The protective cover of claim 1, wherein the second portionis hinged to the first portion.
 10. The protective cover of claim 9,wherein the hinge is on the leading side of the fabric.
 11. A method ofapplying a protective cover to a seam in a press fabric, comprising thesteps of: attaching a protective cover first portion to a press fabricfirst seam portion; wherein the first seam portion is on a leading edgeof the press fabric, and wherein the protective cover first portion isattached to a roll side of the press fabric.
 12. The method of claim 11,wherein the first portion is attached to the first seam portion using atleast one of needling and an adhesive.
 13. The method of claim 11, thepress fabric having seam loops, wherein the first portion is attached tothe first seam portion off center of the seam loops.
 14. The method ofclaim 13, wherein the first portion is attached approximately 4 mm infront of the seam loops.
 15. The method of claim 13, the protectivecover further comprising a second portion, wherein the second portionextends over the seam loops.
 16. The method of claim 11, wherein theprotective cover is at least one of a scrim, a solid film, a plasticmaterial, a woven material, and a non-woven material.
 17. The method ofclaim 11, wherein the protective cover is permeable or impermeable.